Compensating scroll chuck



H. E. SLOAN ET AL CCMPENSATING SCROLL CHUCK Filed March 21, 195e Mach 4, 1958 INVENTORS, Hang/E AS/oaf; QZba/y C70/azi? COMPENSATING SCRGLLA CHUCK Harry E. Sloan, Hartford, and Alban Collette, Newington, Conn., assignors to The Cushman Chuck Company, Hartford, Conn., al corporation of Connecticut Application March 21, 1956, SerialNo. 572,911

3 Claims. (Cl. 279-416) This invention relates to chucks in general, and to Va self-compensating universal chuck in particular.

The type of universal chuck to which the present invention Arelates is customarily hand-operatedl insofar as the jaw-operating mechanism is concerned, and the latter includes a well-known rotary scroll disc the scroll thread of which meshes with teeth on the jaw carriers for simultaneously moving the jaws thereon into and from gripping engagement with work on operating the disc in opposite directions. For its operation in opposite directions, the scroll disc is customarily provided' with bevel teeth which mesh with manually operable gear means in the chuck body. In` order to maintain the scroll disc in` proper mesh with both, the jaw carriers and also the manual gear means, the scroll disc is customarily journalled in the 'chuck body for independent rotation about the center axis Vof the latter. Accordingly, the jaws of a scroll chuck, besides functioning to. clamp work, assume the further function of also `centering the work.

Universal chucks of the aforementioned scroll type are advantageous in many respects. Thus, chucks. of Ythis type are relatively `low in cost,y lend themselves to rapid chucking of work, 'and may quickly be operated by hand. Also, they are adaptable to many different Vkinds of work of widely. different dimensions. Nevertheless,v chucks of this type are limited in their use to Work which is permitted to be centered thereon by the gripping jaws thereof and, hence, do not lend themselves to a large class of special work requiring centering' independently fromV the gripping jaws, such as work of which the real center of the surface portions being gripped by the jaws is inherently off, or may be E, with respect to al desired center with reference to which the work is to be operated on, for instance. To accommodate-this special work, therefore, recourse is had to compensating-type chucks, other than scroll chucks, on which the work is centered by means other than the gripping jaws, and the latter have some freedom to oat so as to grip the work with equal force despite possible or inherent or-center condition of the work surface being gripped. While these compensating-type chucks are entirely satisfactory for this special work, they lack certain of the important advantages of scroll-type chucks. Thus, the known compensating-type chucks are of more complicated construction, and hence higher in cost, than scroll-type chucks, and customarily require additional power equipment for their jaw operation.

lt is the primary aim and object of the present invention to provide a scroll-type chuck featuring jaw selfcompensation, thereby to make available for work of the aforementioned special kind a chuck of this type with all its aforementioned important advantages.

Thus, -it is among the objects of the present invention to provide a chuck of this type of which the scroll disc is bodily oatable in any direction in a plane at right angles to the chuck axis, and is in any position in this plane, and even while floating therein, operable 1n opi arent ICC i posite ydirections to move the jaws into and from gripping engagement with work which is centered on the chuck by means other than the jaws, thereby causing all jaws to come rst into uniform engagement with the work despite unevenness or off-center condition .of the work surface being engaged thereby, and thenV to grip the work all at once withthe same force, on merely operating the scrollv disc in the properV direction for jaw-closure on the work.

It is another object of the present invention to pro.- vide a self-compensatingA scroll chuck of this type, which for its self-compensating jaw action relies on oatability of the scroll disc as aforementioned, and in which the scrolldisc is theV only lioatable part, its manually operable gear means being mounted in conventional non-tioating fashion, thereby to obtain a compensating scroll chuck with the, leastdeparture from the approved' construction, and withno departure whatever from the approved'manip. ulation of the jaw-operation mechanism, of the aforementioned conventional non-compensating scroll chuck and approximately at the same, or only slightlyY higher, cost as the latter.

Another object of the present invention` is to provide a self-compensating scroll chuck of this type in which the aforementioned conventional non-floating mounting of the manually `operable gear means for the scroll. disc is achieved, despite the oatability of the latter, by dividing the scrolll disc. with its customary scrolly thread and bevel teeth on opposite faces thereof into two separate parts or discsA of which one, is a, non-Hoatingly journalledV bevel gear andY the other aA floatingly mounted., scroll, and by providing a simple llexible -coupling between these parts, such as aradially floatable pin-type driving connection, for instance.l

Other objects and advantages will appear to those skilled in the, art from the following, considered in conjunction with the accompanying drawings.

In the accompanyingdrawings., in which certainmodes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a. front view of a compensating scrollv chuck embodying the present invention;l

Fig. 2 is a longitudinal section throughY the chuck as taken` substantially on the .line 2--2 of Fig. l, and with its operating parts shown in relation to certain exemplary gripped work;

Fig. 3 is another front view o f the chuck, but showing Vcertain operating parts thereof in relation to the exemplary gripped Work;

Fig... 4 isa fragmentary section taken substantially on the line 4 4 of Fig. 2; and

Fig. 5v is ay fragmentary section similar to Fig. 4, showing an alternative arrangementA .of certain parts of the chuck. Y

Referring to the drawing, and more particularly to Figs. l andA 2. thereof, the referencev numerall 10 designates a compensating universal chuck having `a body 12 withv a longitudinal axis x-x which for most applications of the chuck Iconstitutes therotary axis of the latter. The chuck bod-yV l2 is, in the present instance, formedv of complementary Vfront and lrear sections 14 and 16, respectively, of' which the front, section 14 has guideways 18: in which jaws 2,0are movable into and from gripping engagement with work W, and both -bodyl sections 14, 16 have jaw-operating mechanism 22 nested therebetween. -n the present example, the Vfront body section 14 is provided with three equangularly-spaced radial guideways 18 for the jaws 20.

The front body section 14 has in its rear 1an annular recess Z4 leaving `the same with :a central hub 26 and of theV lathe on which'the chucktis mounted,

Y Ya. peripheral'skirt 28 of which the hub is ttedly received i111V an'annular Y'recess/30 in the' rear body sectionV 16 for accurate location ofthe frontY section 14 thereon. The companionlbody sections V`14 .andY 16 are, 'in Vthe present instance, held in `releasablyjY assembled vrelationv/ithA each gotherby'aY-plur'alityY .of boltst32 whichrser've fa'lsofor the releasable attachment vofthechuckto a lathe or other machine tool 34.2The'bo1ts 32 are totthis Vendthr'eadedly received at 36;'by'the` power spindle` 38 inthe hfcadA of the machine tool, .and vthe chuckvgmayaccurately Vbe locatedron the power-spindle itlbythefittedV reception of the latter in an annular recess 42 in therear Vsection 16 of the chuck body.; Ifdesired, an additional bolt'or Y boltslnot shown) may, extend fromvthe Yfrontbody section 14 finto, andrbefthreadedly receivedby, the rear Y Y section Y16 inV order to hold them in theirY assembled rela- Y t tonl'when thefchuck is removed from lthe machinetool.

nalled in a bore 72'formed partly in each ofthe 'body sec- "tions14 and'16, and is held against-axial movement by i a key 74 .which is locked'inthe front body section 14 and projects into a peripheral groove `76 Yin the bevel l pinion so that the latter may be turned in opp'ositedirec-V Y Y v tions, having toV this end asocket 78 for the reception of Y 'a suitable wrench.

l Therinstantochuch being'f a compensating type, inf clude's at leastQaV suitable` mounting for equipmentwith which to centerwor'kfon'the chuck by means other than the work-'gripping Vjaws 20, the work-centering equipment Y to be provided eitherV by4 the,Y chuck manufacturer as, part of the chuck,l as Vusual,orV byjthe Vuser Vof, the chuckV in some'cas'esl rrInthe present'example, `the mounting in the 'chuck' for suitable work-centering' equipment Yis in the Vformryof va 4central threadedhole 44 in therearYbody s'ection V16 lfortheV reception Yof a threaded shank 46 of a suitable vWork center. YIn 'the present example also, the Y workcenter, designated-by the reference 'numeral 48, is in theformiof a locating pin or stub on which the exemplary work W is received with its machined-,center'bore 50 theV axis of which thus coincidesjtwith thechuckaxis V'.it--x andrrmay,V constituterthe Yreference axis for a further Y external machining operation or operations, fortinstance,

on the work while the same is gripped .by the jaws' 2t) Vin 'preference to the'grip of aco1let,tf,or instance, in the center bore 5G thereof.

Of course, the'rinstant chuck may,

Y will Abe compelled Y to float'or yield',lil1to the,exemplaryY eccentric position Yshown in VFigsfZ and v3, after the -rst Y in lieurof the exemplary 'work locating pinf48 andrforY t Vother work to befgripped, be provided with a conventional 'Y YYtapered center (not shown) on which toYlocate the adjacent ,endgof the work, in which case theV opposite center for ,the'otherrendtof the Work may be carriedby the'tailstoc f The Vjaw-operating mechanism comprises, in the present instance,fa'.scrolltype jawactuator 54`andY operating gear therefor. 4In accordance with'thepresent invention,` the scroll-typejawactuator 54, contrary to` being a convent Further in accordance withrthe presentinventiom'there isrprovided between the bevel gear 58 and th scroll 56V Y t va tiexible coupling 80'which permits the latter'tooaas Vaforementioned, despite its driving connection'withthe journalled bevel gear 58.Y YIn' the present example, this exible coupling 80 .is of the single slidertype, thebevel' gear 53 and scroll S6 being tov this end provided withan eccentric projecting pinV or flug formation'SZ and a radial. grooveft, respectively, of which the'former projects into the latter (Figs. 2 and"4). While the lugY formation 8,2V

on the bevel Vgear 58 isshown Vin Fig..4 to havefsnbstantiallya sliding tin the *radial groove 84 in the scrollYY56, YFig. 5 shows an alternative` coordination, ofthe lug forma-V tion 82' onV the bevelgear with the radial groove84 inY the scroll 56', in that the -lug formation 82 islfof a Vdiameter which, is smaller than `the width; of `thegro`over84f and,hence, has some lateralfreedom Vin, or clearance Yfromsaidgroove.V Y, t t 1, Y l, Y v

Letit now. belassumed` that the exemplarytworkLW, Y

centered on the locatingrpin r 48 fintthe exemplaryangular position shown in Figs. `2 and 3,yis to begrippedby the' jaws 20; atritsrend flange 8.4 and that the latter isforY any reason V eccentric with respect to the axis of the center bore`50Y therein to the extent shownY in Fig '3 inwhich xf'designates the truejcenterV axis-of the endfange4'.V Under thesecircumstances, ittrstands torreason that 1onoperating the bevel pinionY 70 intheV proper directionv to causeclosureof the jaws 20ton the-Work'Wvthescroll'S one* or two jaws engage '.thee'nd lllangem84lofttlj1eV lwork and whilethe remainingrjaw or jaws'Yclosetinj on theeamjc, for uniform engagementgof all jaws Vwith .lthef exemplary Y Veccentric end ,flangeA 84-on the centered work W,is'postional onepiece scroll disc with its customary scroll thread Y Y and falso bevel gear teeth, is provided inttwoseparate parts-56 Yand 58, of which the part V56/ is aYscroll member t and the part 58 is its gear member, in this instance a'bevel 'ing part ofthe operating gear for the scroll member hereinafter simply referred-to as scrollf is'journalled on j the `hub 26 of the front body section 14 for rotation about sible only onYrassurnption byrtherscroll S6 Offacoinc'ident eccentricflposition.V Hence, itis only .after- Vall thefjaws-V y 20 are in uniform engag'ement'with theeccentric'work harige 84 and the scroll 56 has floated into axial aligny ment withrthe true center -x of thesa'melFig. 3),"that the jaws will, oncontinued forc'edroperation 4of thebevelpinlv ion 70 sin the sarne` direction, Vsimultaneously exertrthe sameqgripping force -onlthe work `flange. 84.V lfl'he Work Y may now be machined, as by turning` part ofthe sin'iila'rlyV Y eccentricv body 86 thereof, for instance, cylindricalwith, respect to the axis of the center Vbore 50VV thereofwhich in this case coincirdesrwithV the chuck axis V.xe-2c.'

` It will nowYbe appreciated that,by virtueV of the sepa'-k Vrate arrangements` of the'scrollro andof its .operating mechanism and ,thel provision or Va exible couplingbe-Y tween them, and by the further pl'Qvision'of at least a mountingrfor work-centeringcmeans,V theinstant ,scrollthechuck axis rf-x, whilethe "scroll 56Vis-bodily'oat- Y able, Yin` any direction in a plane at Yri'ghtan'gl'es to the Y chuckjaxis xY-x, Within limits defined by the maximum 'outer Yand inner gaps Vg and g' between the scroll 56 and the skirt 28 and hub 26, respectively, ofthe front body section 14 Y(Figs.` 2 and 3). The scroll'56 is Yat its Vfront provided with aconventional spiral or scroll thread or tooth 66'which is in mesh with corresponding tooth forf mations 68 in back of the guided jaws 20.1 VThe meshing Y Ythread 66 of the scroll 56,-and toothformations`68 of the jaws 20 are preferably kept lubricated by grease admitted thereto throughY a nipple 69 inthe frontV bojdyYYsection 14.

I t The operating device for the'sc'rollY56 further includes', ,75

in the present instance, a bevel pinion 70 which is jourtype chuck vis trulycompensatingrin itsaction on all kinds of work. Thus, the instanttcompensating scroll chuckV lends itself to any kind of work of which'the surfaceYV or surfaces to be gripped by the jaws areo with respectto Y a reference laxis onwhichithework is to be`Y centered VKby meansV other tharrtheA gripping/jawgand whichgin mostk cases -will be coincident with the center axis of the chuck. Y Y

YIn this connection also/,itis fully within the purview of :the present invention toarrange thechuck for centering t,

work externally and arrange the jaws for their internal grip onV the work.

' the'present embodimentsare,therefor@to be considered Yin,Yall:respects.,as illustrativeand not restrictive,4 and all changes Ycoming within themeaning and equivalency The inventionmay be carried outin othe'rspecific/ ways Y thanfthoseherein set forth without departing from the spiritV and essential; characteristics of theinvention,,andV

asaasva range ofthe appended claims are intended to be embraced therein.

What is claimed is:

1. A compensating universal chuck, comprising a chuck body having a longitudinal axis and a mounting for workcentering means; jaws on said body and guided thereby for movement into and from gripping engagement with work; a scroll member bodily oatable in said body in a plane at right angles to said axis and operatively connected with said jaws to move them into and from uniform gripping engagement with centered work on turning said scroll member in opposite directions, respectively; an operating means for turning said scroll member including another member journalled in said body for rotation about said axis and a exible coupling between said members to permit said scroll member to iioat relative to said other member.

2. A compensating universal chuck as set forth in claim 1, in which said coupling is formed by an eccentric pin on one of said members and a substantially radial groove in the remaining member into which said pin projects.

3. A compensating universal chuck as set forth in claim 1, in which said other member is a bevel gear, and said operating means further includes a manually operable bevel pinion journalled in said body and meshing with said bevel gear.

References Cited in the le of this patent UNITED STATES PATENTS 

